alexdax Posted September 9, 2014 Share Posted September 9, 2014 help me out guys i´m going to rebuild my engine and i´m now considering the vortech pulley sizes. my question is: if i want a linear power curve and reach the max power at 7.000rpm i will have to stay with the 3.12 pulley? this is my calculations: if my V-3 has a peak efficiency of 75% and a max 53.000 rpm i guess that the max efficiency is reached at 39.750rpm and so the max efficiency is reached at 6252 rpm theoretically after the 6252rpm i will see a power drop on the dyno? my question is: what happens after after peak efficiency is reached? the pulleys just oscillate the power on the rpms curve? do i need a smaller pulley? in my calculations the smaller pulley will be allot far from the peak efficiency! does it matter? Quote Link to comment Share on other sites More sharing options...
GMballistic Posted September 9, 2014 Share Posted September 9, 2014 All I know is that upgrading the pulleys brings the boost on sooner and gives you more of it. For the non-REVUP kits, the 3.12 pulley adds about 25whp more than the stock 3.33 pulley while the 2.87 pulley adds about 30whp more than the 3.12. There's also another step up you can do with changing the cog pulley that drives the 2nd smaller belt attached to the vortech. Changing it to a 34 tooth pulley can possibly give you more power too, however some people experienced a power loss with the 2.87+34/28 cog setup. Have a good read through this thread and I'm sure you'll find all the answers. Link: http://my350z.com/forum/forced-induction/270770-vortech-faq-read-this-before-asking-vortech-questions.html Hope that helps. Quote Link to comment Share on other sites More sharing options...
evilscorp Posted September 9, 2014 Share Posted September 9, 2014 (edited) No, power only goes up as the revs rise as you spin the blower faster, smaller pulley= blower spins faster at lower rpm. What you need to calculate is how fast can you spin your blower. Efficiency is due to parasitic losses that supercharger creates. Sorry phone ran out of battery. Off you go on vortechs website you can calculate the speed you are spinning your blower, I.e. aim for 53k so that might mean lower rev limit but change to smaller pulley or change cog setup or crank pulley size etc. Edited September 9, 2014 by evilscorp Quote Link to comment Share on other sites More sharing options...
alexdax Posted September 9, 2014 Author Share Posted September 9, 2014 No, power only goes up as the revs rise as you spin the blower faster, smaller pulley= blower spins faster at lower rpm. What you need to calculate is how fast can you spin your blower. Efficiency is due to parasitic losses that supercharger creates. in that case if i install a 2.62 pulley i will be exactly with 53.000rpm on the V3 at 7.000rpm. but the max efecciency of the V3 will be at 5250rpm. what i will see is a decrase in power curve after 5250rpm but still adding power! Right? Quote Link to comment Share on other sites More sharing options...
alexdax Posted September 9, 2014 Author Share Posted September 9, 2014 All I know is that upgrading the pulleys brings the boost on sooner and gives you more of it. For the non-REVUP kits, the 3.12 pulley adds about 25whp more than the stock 3.33 pulley while the 2.87 pulley adds about 30whp more than the 3.12. There's also another step up you can do with changing the cog pulley that drives the 2nd smaller belt attached to the vortech. Changing it to a 34 tooth pulley can possibly give you more power too, however some people experienced a power loss with the 2.87+34/28 cog setup. Have a good read through this thread and I'm sure you'll find all the answers. Link: http://my350z.com/fo...-questions.html Hope that helps. thanks but e read it like 1000 times Quote Link to comment Share on other sites More sharing options...
evilscorp Posted September 9, 2014 Share Posted September 9, 2014 No I don't think the efficiency is exactly at 75% in the power band, it could be anywhere (more likely higher up) but the amount of energy converted from rotating (being spun by the belt) could only ever be a max of 75% as heat/noise etc will loose you that 25% of the energy you put into spinning the blower. Basically ignore the75% it's about fuel efficiency and boring stuff 1 Quote Link to comment Share on other sites More sharing options...
alexdax Posted September 9, 2014 Author Share Posted September 9, 2014 (edited) No I don't think the efficiency is exactly at 75% in the power band, it could be anywhere (more likely higher up) but the amount of energy converted from rotating (being spun by the belt) could only ever be a max of 75% as heat/noise etc will loose you that 25% of the energy you put into spinning the blower. Basically ignore the75% it's about fuel efficiency and boring stuff ok the efficiency peak was the variation that was annoying me. i should only take in consideration the max rpm of the blower ? Edited September 9, 2014 by alexdax Quote Link to comment Share on other sites More sharing options...
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